Improve stubs with minor fixes (#1038)

* Add a missing attribute to Jinja2.

https://github.com/django/django/blob/main/django/template/backends/jinja2.py#L35

Signed-off-by: Zixuan James Li <p359101898@gmail.com>

* Make _QuerySet.extra's signature more generic.

This makes sure that we don't reject tuples, which is also valid
according to the implementation.

Relevant source code:
https://github.com/django/django/blob/03eec9ff6cc78e7c1bcf88bb76ecd11f0d433c72/django/db/models/sql/where.py#L271-L281
https://github.com/django/django/blob/03eec9ff6cc78e7c1bcf88bb76ecd11f0d433c72/django/db/models/sql/query.py#L2307-L2308

Signed-off-by: Zixuan James Li <p359101898@gmail.com>

* Fix user_passes_test to use AUTH_USER_MODEL.

According to the documentation, `test_func` is a callable that takes a
`User` (possibly anonymous).

Relevant documentation:
https://docs.djangoproject.com/en/4.0/topics/auth/default/#django.contrib.auth.decorators.user_passes_test

Signed-off-by: Zixuan James Li <p359101898@gmail.com>

* Add more accurate type annotations for dirs.

Though not documented, it's possible for `dirs` to contain
`pathlib.Path`.

`django.template.loaders.app_directories.Loader` is an example for this:
https://github.com/django/django/blob/03eec9ff6cc78e7c1bcf88bb76ecd11f0d433c72/django/template/loaders/app_directories.py
https://github.com/django/django/blob/03eec9ff6cc78e7c1bcf88bb76ecd11f0d433c72/django/template/utils.py#L97-L111

Signed-off-by: Zixuan James Li <p359101898@gmail.com>

* serve should return FileResponse.

There are several serve functions that should return a `FileResponse`.

Source code:
https://github.com/django/django/blob/863aa7541d30247e7eb7a973ff68a7d36f16dc02/django/views/static.py#L17-L53
https://github.com/django/django/blob/863aa7541d30247e7eb7a973ff68a7d36f16dc02/django/contrib/staticfiles/views.py#L15-L39
https://github.com/django/django/blob/863aa7541d30247e7eb7a973ff68a7d36f16dc02/django/contrib/staticfiles/handlers.py#L48-L50
https://github.com/django/django/blob/863aa7541d30247e7eb7a973ff68a7d36f16dc02/django/test/testcases.py#L1680-L1687

Signed-off-by: Zixuan James Li <p359101898@gmail.com>

tests/typecheck/contrib/auth/test_decorators.yml

@@ -27,14 +27,14 @@
 -   case: user_passes_test
     main: |
         from django.contrib.auth.decorators import user_passes_test
-        @user_passes_test(lambda u: u.username.startswith('super'))
+        @user_passes_test(lambda u: u.get_username().startswith('super'))
         def view_func(request): ...
         reveal_type(view_func)  # N: Revealed type is "def (request: Any) -> Any"
 -   case: user_passes_test_bare_is_error
     main: |
         from django.http.response import HttpResponse
         from django.contrib.auth.decorators import user_passes_test
-        @user_passes_test  # E: Argument 1 to "user_passes_test" has incompatible type "Callable[[Any], HttpResponse]"; expected "Callable[[AbstractUser], bool]"
+        @user_passes_test  # E: Argument 1 to "user_passes_test" has incompatible type "Callable[[Any], HttpResponse]"; expected "Callable[[Union[AbstractBaseUser, AnonymousUser]], bool]"
         def view_func(request) -> HttpResponse: ...
 -   case: permission_required
     main: |

tests/typecheck/managers/querysets/test_from_queryset.yml

@@ -407,7 +407,7 @@
         reveal_type(MyModel.objects.difference)  # N: Revealed type is "def (*other_qs: Any) -> myapp.models.MyQuerySet[myapp.models.MyModel]"
         reveal_type(MyModel.objects.distinct)  # N: Revealed type is "def (*field_names: Any) -> myapp.models.MyQuerySet[myapp.models.MyModel]"
         reveal_type(MyModel.objects.exclude)  # N: Revealed type is "def (*args: Any, **kwargs: Any) -> myapp.models.MyQuerySet[myapp.models.MyModel]"
-        reveal_type(MyModel.objects.extra)  # N: Revealed type is "def (select: Union[builtins.dict[builtins.str, Any], None] =, where: Union[builtins.list[builtins.str], None] =, params: Union[builtins.list[Any], None] =, tables: Union[builtins.list[builtins.str], None] =, order_by: Union[typing.Sequence[builtins.str], None] =, select_params: Union[typing.Sequence[Any], None] =) -> myapp.models.MyQuerySet[myapp.models.MyModel]"
+        reveal_type(MyModel.objects.extra)  # N: Revealed type is "def (select: Union[builtins.dict[builtins.str, Any], None] =, where: Union[typing.Sequence[builtins.str], None] =, params: Union[typing.Sequence[Any], None] =, tables: Union[typing.Sequence[builtins.str], None] =, order_by: Union[typing.Sequence[builtins.str], None] =, select_params: Union[typing.Sequence[Any], None] =) -> myapp.models.MyQuerySet[myapp.models.MyModel]"
         reveal_type(MyModel.objects.filter)  # N: Revealed type is "def (*args: Any, **kwargs: Any) -> myapp.models.MyQuerySet[myapp.models.MyModel]"
         reveal_type(MyModel.objects.intersection)  # N: Revealed type is "def (*other_qs: Any) -> myapp.models.MyQuerySet[myapp.models.MyModel]"
         reveal_type(MyModel.objects.none)  # N: Revealed type is "def () -> myapp.models.MyQuerySet[myapp.models.MyModel]"